Automatic oil well dewaxing system



Dec. 22, 1970 GHoR L-EY 3,548,438

AUTOMATIC OIL WELL DEWAXING SYSTEM Filed June 26. 1968 CONTROLLER POWE R SUPPLY DWARD L GHORMLEY United States Patent 3,548,438 AUTOMATIC OIL WELL DEWAXING SYSTEM Edward L. Ghormley, Woodland Hills, Calif., assignor to North American Rockwell Corporation Filed June 26, 1968, Ser. No. 740,362 Int. Cl. B08b 9/04 US. Cl. 104.06 2 Claims ABSTRACT OF THE DISCLOSURE ture of the tool above the melting point of contaminants which collect on the tool, such as wax. Means are also provided for flushing the tool and housing to remove the melted contaminants.

BACKGROUND OF THE INVENTION This invention pertains to the field of oil well dewaxers and more particularly to a dewaxing system which utilizes a cleaning tool for scraping the Wax in combination with a heating element for cleaning the tool.

One of the problems encountered in the oil well art is that of cleaning paraffin and other contaminants from the insides of flowlines.

Various devices have been inserted into the flowline for the purpose of cleaning it out. Forexample, spherical pigs and elongated scraping tools have been used with particular frequency.

In US. Pat. No. 3,171,487, entitled Parafiin Cutter, by I. L. Ault, there is disclosed an elongated scraping tool which is forced through the flowline for cleaning and which is stored in a tool housing when it is not in use.

Another device which is of interest, to show the state of the art, is disclosed in US. Pat. No. 3,268,007, entitled Paraffin Cleaner for Well Tubing by D. S. Bodie. In that patent, there is disclosed a scraping tool which has coil springs mounted to each of its ends. In operation, the coil springs vibrate making contact with the walls of the flowline scraping and dislodging deposits of paraffin and other foreign material from the walls of the flowline. The tool, when not in use, is stored in a tool housing which is permanently aflixed to the flowline.

Another patent of interest, only to show the state of the art, is US. Pat. No. 1,989,035, entitled Apparatus for Cleaning Oil Wells, by E. A. Blum.

All of the above patents fail to show a heating means coupled to the tool housing for melting the contaminants picked up by the tool during the cleaning process, along with a means for flushing the tool and the tool housing clean of these contaminants.

SUMMARY OF THE INVENTION In the preferred embodiment of the invention, a tool holder is adapted to be aflixed to a section of flowline. The tool holder is adapted to store in a ready position a cleaning tool such as through the flowline (TFL) scraping tool. Heating means are positioned in proximity to the tool holder to raise the temperature of the holder and the tool contained therein above the melting temperature of contaminants contained on the tool. Means are connected to the tool holder for flushing the contaminants from the holder and the tool. The heating means may be an electric heating coil wound around the tool holder and provided with a source of electric power from an external source. The flushing means may, for example, be a reserp CC voir of oil which is forced into the tool holder under pressure and which is drained out of the system when the contaminants are suspended therein.

Accordingly, it is an object of the present invention to provide an improved flowline cleaning device.

It is a further object of the present invention to provide a novel system wherein the cleaning tool is also cleaned and the system is purged of contaminants.

It is another object of the present invention to provide a tool cleaning system wherein the contaminating material is melted and flushed away.

The aforementioned and other objects of the present invention will become more apparent when taken in conjunction with the following description and drawing and which drawing forms a part of this application.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a partially sectioned view of the preferred embodiment of the invention.

BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawing, the tool holder 10 which is an elongated cylinder is attached to a flowline 12 by means of a coupling 19. A cleaning tool 20, such as a TFL cleaning tool, is adapted to be housed within the housing 10. A gate valve 14 is interposed in the path of the flowline 12 to cut off the housing 10 from the fluid pressures generated in the flowline. When valve 14 is open, the opening is of such a diameter that tool 20 can pass therethrough into the flowline proper. The cleaning tool 20 is comprised of two or more articulated sections, a scraper unit 22 and a piston unit 21 connected by a universal joint fixture 23, which allows the elements 21 and 22 to move with respect to each other such that the tool can negotiate curved sections of the pipe. Various types of tools may be used and the one shown is by way of example only and is not to be taken as a limitation on the disclosure. A heating means 25 is positioned in close proximity to the tool holder 10 in order to raise the temperature of the tool 20 above the melting temperature of any contaminants that may be attached to the tool. The heating means 25 is comprised of an electrical heating element 28 attached to a portion of the tool holder 10, with a power supply 26, for supplying electrical power to the heating coil, a temperature sensor 29, such as a thermostat for sensing the temperature in the housing 10 and for providing an electrical signal to a controller 27 for turning the power supply 26 off and on depending upon the temperature sensed.

Flushing means 42 for flushing the tool 20 and the inner portion of the housing 10 clear of the contaminating material is comprised of; a source of liquid 34 under pressure, the pressure to be provided by an auxiliary pump 50 which is connected to a liquid reservoir tank 51 with the output from the reservoir tank connected to the tool housing 10 by means of sections of pipe 30 and control valves 32 and 40, with a second section of pipe 36 positioned below the tool holder to allow the contaminated fluid to drain out of the holder. The output of the flowline 12 normally proceeds along the pipe 16 through the shut-off valve 18 to some sort of storage or utility device.

In a flowline cleaning operation, valve 18 is closed, valve 14 is opened, pump 50 is started and valves 32 and 40 are opened and valve 101 is closed to push the tool 20 into and through the flowline 12. When the tool has completed its cleaning job, valve 101 is opened and valve 40 is closed which allows the normal pressure of the well to push the tool 20 back into the housing 10. Valve 18 is then opened, valves 14 and 101 are closed to allow normal production to proceed from the well. The housing 10 is fitted with crude oil from reservoir 51 by opening valves 32 and 40. Valves 32 and 40 are then closed. Heater means 25 is activated to bring the temperature of the liquid within the housing and in turn the temperature of the tool up to a level which is sutficient to melt the contaminants that stick to the tool. Once all of the contaminants have been melted and suspended in the liquid within the housing 10, the valve 38 may be opened and the liquid allowed to drain out; this fluid flow will be augmented by the increased vapor pressure of the heated fluid. By cracking valve 14 slightly, some of the crude oil from the flowline will Wash and clean tool 20. When the cleaning process is complete, the heating means can be disengaged ready for subsequent cleaning operations.

Although an electrical heating means is shown, it would be obvious to those persons in the art that other means such as radioisotope heating, or steam circulated through pipes surrounding the outer wall housing might also be used to bring the temperature of the tool up to a level which is above that of the melting point of the contaminants normally found on the tool. Or, a heated oil stream can be circulated through the tool holder 10.

While there has been shown what is considered to be the preferred embodiment of the present invention, it will be manifest that many changes and modifications may be made therein, without departing from the essential spirit of the invention. It is intended, therefore, in the annexed claims, to cover all such changes and modifications as may fall within the true scope of the invention.

What is claimed is: 1. In combination: a cylindrical tool; an elongated cylindrical holder for holding said tool in a stored position; heating means for raising the temperature of said tool above the melting temperature of contaminants on said tool; means for flushing said tool clean of said melted contaminants;

- 4 v3,..3 n V a flowline carryinga pressurized fluid, said flowline connected to said elongated cylindrical holder;

a valve interposed in said fiowline to allow said tool to pass into said flowline and to control fluid How to said tool holder; and

pressurized fluid means connected to said elongated cylindrical holder to force said tool from said holder into said fiowline against the pressure of said fiowline.

2. In combination:

a cylindrical tool;

an elongated cylindrical holder for holding said tool in a stored position;

heating means for raising the temperature of said tool above the melting temperature of contaminants on said tool;

means for flushing said tool clean of said melted contaminants;

a reservoir of liquid connected to said elongated holder;

means for pressurizing said liquid; and

valve means interposed between said liquid reservoir and said elongated holder to control the flow of fluid through said elongated holder.

References Cited UNITED STATES PATENTS 1,739,695 12/1929 Slauter l34lO5UX 2,415,729 2/1947 Dana 1345X 2,527,666 10/1950 Winter 134-105X 3,404,421 10/1968 Surber l5104.06(A) 3,425,083 2/1969 Wennerberg et al. l37268X ROBERT W. MICHELL, Primary Examiner US. Cl. X.R. 134l68 

